A novel maximum power point tracking strategy based on optimal voltage control for photovoltaic systems under variable environmental conditions

摘要

From the engineering cybernetics perspective, determining the output voltage of a solar cell corresponding to the maximum power point (MPP) under variable temperature and irradiation conditions is essential for tracking the maximum power point. However, conventional methods could not effectively achieve this goal, and approaches for utilizing this information do not exist, including the output voltage and duty cycle at MPP, in the control process. This paper describes a novel method for maximum power point tracking (MPPT) control in parameter optimization corresponding to variable environmental conditions. The results show a definable nonlinear relation between variable environmental parameters and the output voltage of a solar cell at MPP both theoretically and experimentally. Additionally, this research gives the mathematical expression for it. Then, MPPT control rules are created based on the findings from a nonlinear relation that can respond at high speeds to variations in irradiation and the temperature of a solar cell. In view of this relationship, we found that the output voltage at MPP is robust to irradiance in a certain range, and this directs the choices of irradiance in experiments. Therefore, MATLAB (R)/Simulink (R) numerical simulations are presented to illustrate that this control algorithm can implement the MPP of a PV generation system efficiently even in the low solar irradiation condition. (C) 2015 Elsevier Ltd. All rights reserved.